A Novel Out-of-Step Protection Algorithm Based onWide Area Measurement System

This paper proposes a novel Out-of-Step protectiontechnique based on synchronized phasor measurements andconcept of Equal Area Criterion (EAC). In any disturbance, inthe control center, generators are clustered into safe and riskgroups based on the concept of Boundary of Angle Oscillations.At the same time, a local stability index also is sent to the controlcenter from each generator. The latter is obtained by localphasor measurements based on EAC concept. Generator isknown as unstable if it belongs to the risk cluster at the controlcenter and its stability index is lower than one. For eachgenerator, the acceleration area during fault condition iscalculated directly using the generator output power and rotorangle measured in real-time. As soon as the fault is cleared, thedeceleration area is predicted with the help of post-fault curveestimated by the least square method. The proposed technique isverified on the New-England ۳۹-Bus test network.

Keywords:

Out-of-step , equal area criterion , boundary of angleoscillations , least square method , phasor measurement unit (PMU)